Is it possible to close doors in X-Com: Enemy Unknown?

Question

I know left-click would open a closed door without making too much sound, lifting some fog of war. Is there a way to close them back, giving yourself some tactical defense in protection-type missions?

Answer 1

No, once you opend a door, it remains open, which is why you should open doors only when you are really ready for what may be inside.

I also recommend ending your turn first before you open a door to be able to efficiently combat everything that may jump out.